Return the created PBXBuildFiles from PBXNativeTarget#add_file_references
Yield PBXBuildFiles for improved convenience
Add symbol getter and setter for dst_subfolder_spec to PBXCopyFilesBuildPhase
[Spec] Fix plurals
[Changelog] Add entry for #187
Merge pull request #187 from mrackwitz/minor_api_improvements

Minor API Improvements
Drop support for Ruby < 2.0.0